In general, the present invention relates to an apparatus used typically in genetic transformation of the higher plant. In particular, the present invention relates to a laser apparatus for boring a hole through a cell wall of a plant for injecting foreign genetic materials and a genetic recombination method using this apparatus.
In the conventional genetic transformation of the higher plant, typically, a premature embryo is taken out from a seed cut from a panicle of a mature plant and cultured or a seed with the seed coat thereof removed is budded. There is adopted a method of culturing an embryo or a porphyritic texture by using a means for accelerating and injecting inactive carrier particles coated with a replicative substance of a nucleic-acid organization into a somatic cell obtained by cutting out a split porphyritic texture from a nursery plant as disclosed in the specification of U.S. Pat. No. 5,149,655 with the title "Apparatus for Genetic Transportation." The method is referred to as the particle-mediated genetic-transformation method.
By the way, in the particle-mediated genetic-transformation method, since a somatic cell of a plant is protected by a cell wall with a thickness of several microns which cell wall is composed of mainly layers of a very stiff fiber material made of cellulose and pectin layers between the cellulose layers, in order to break the wall of the somatic cell, physical bombardment of tungsten or gold particles with a diameter of about 1.2 microns into the embryo is required. For this reason, a pistol or an air rifle is used.
When a particle-mediated genetic transformation is carried out by means of a pistol or an air rifle, however, it is feared that the somatic cell of the embryo itself is damaged by the energy of the particles used in the bombardment. Thus, the resulting yield is not necessarily high. As a result, it is necessary to prepare a large number of embryo cells and a large amount of replicative substance of the nucleic-acid organization. On the top of that, the use of a pistol or an air rifle is dangerous. In addition, it is also necessary to get a license of using explosives of firearms, giving rises a lot of miscellaneous related work.